Water quality assessment of the Siluko River,southern Nigeria

The water quality of the Siluko River, Edo State, Nigeria was investigated from March to August 2015 to determine its suitability for drinking and usage for domestic purposes. Water samples collected from three stations were tested for thirteen physico-chemical parameters using standard analytical procedures. Temperature, phosphate and chloride were significantly different across the three stations. All other parameters, with the exception of turbidity, dissolved oxygen and phosphate, were within the permissible limits recommended by the Nigerian Standard for Drinking Water Quality (NSDWQ) and World Health Organization (WHO). Water Quality Index (WQI) values ranged from 11.24 to 16.15, indicating excellent water quality. While the quality of the water from the Siluko River is suitable for drinking and domestic usage, to prevent future deterioration of the water, it is recommended that the regulating authorities monitor effluents discharged into the river from human activities.     

广东省水资源特点和合理开发利用研究

本文论述广东水资源量,时空分布和季节变化特点,并分析广东用水存在问题,不合理开发利用水资源和浪费水;水库蓄水和调节能力未能满足用水要求;水质污染日渐严重。使水资源渐感紧缺。按目前用水趋势,要达到供需水平衡,必须成立统一管理水资源的流域机构;按不同的经济发展阶段,改变其主要洪水职能;节约用水;增加水库的供水和调节能力;改变调峰发电方式：提高重复用水率;保护水质;做好水土保持工作。最后提出,制定地方经济发展总体规划时,其用水量必须与可能供水量相适应。     

Water quality and Human Health Risk Assessment: a case study of the Czarna Przemsza River source in Zawiercie,Poland

Abstract

The water quality of the Czarna Przemsza River source in Zawiercie was investigated in four sampling campaigns in years 2016 and 2017. Values of 62 indicators (physico-chemical, inorganic, organic, and biological) were compared with permissible limits for drinking water according to Polish legal acts and EU, WHO, USEPA, and Canadian guidelines. The water quality was determined as below good because of EC values and As, Ca, Cd, Cr, Cu, Se, and Zn concentrations. Water was also determined as non-potable due to exceeded concentrations of Al, As, Cd, Cr, Fe, K, Ni, Pb, Sb, and Se. The Human Health Risk Assessment for Zawiercie’s inhabitants was carried out, while water from the source is consumed regardless of its quality. The mean estimated daily intake (EDI) values exceeded Minimal Risk Level values forCr, Cd, As, Se, and Cu. The hazard index (HI) values pointed very high total non-carcinogenic risk in residential exposure scenario generated mainly by As, Cr(VI), Tl, Pb, MCPA, Se, and Cd. Water intake scenario based on questionnaire surveys pointed that risk for inhabitants existed (HI >1). The total carcinogenic risk (R_t) values were at the unacceptable level and decreased in the following order: Cr(VI) > As?>?Pb.     

Physico-chemical and macrobenthic faunal characteristics of Kuramo Water,Lagos, southern Nigeria

A five-month study in 2001 of an enclosed lagoon, Kuramo Water in southern Nigeria, exposed to urban perturbation describes its physical, chemical and macrobenthic invertebrate characteristics. Of the 16 physical and chemical conditions studied at four sites within the bank-root biotope, only BOD and TDS content were significantly different between sites. The elevated level of these perturbation indicators could be related to the raw and treated domestic sewage released directly into Kuramo Water from point and non-point sources. A total of 16 taxa and 691 macrobenthic individuals belonging to 11 families were recognised at the study sites. A naidid and a chironomid species were the most abundant, occurring in high numbers throughout. Other invertebrate groups occurred in low numbers. The diversity indices calculated supported this trend. The generally low diversity further supports the observation that Kuramo Water is a disturbed environment. The absence of molluscs in the benthic invertebrate samples of this study, compared to their dominance in earlier studies of Kuramo Water, reflects a modification in the habitat resulting from a change in the salinity from brackish to freshwater.     

Water quality dynamics in the Boro-Thamalakane-Boteti river system,northern Botswana

The quality of water in aquatic systems is subject to temporal and spatial variations due to varying effects of natural and anthropogenic factors. This study assessed the dynamics of water quality in the Boro-Thamalakane-Boteti river system along an upstream–downstream gradient above and below Maun during February, May, September and December 2012. Temperature, conductivity, pH, dissolved oxygen, turbidity, Escherichia coli and faecal streptococci were monitored in the settlements of Boro, Maun, Xobe, Samedupi, Chanoga and Motopi along the river system. Comparisons of water quality among settlements using ANOVA and Tukey's honest significant difference test highlighted a significant decline in water quality from upstream to downstream, indicated by increases in microbial numbers and turbidity. The quality of water improved as the water level rose during the peak flooding season in September and declined thereafter. This study highlights the possible influence of human settlements and associated developments on waterbodies, and lends strong support to management efforts to maintain river water quality to ensure the suitability of the water for various ecosystem uses.     

宁蒙引黄灌区农田排水沟渠水质特征

黄河上游农业面源污染正在变成影响黄河水质的主要污染源,威胁到下游黄河流域水资源的安全利用。通过对宁蒙引黄灌区排水沟渠土壤和水质的调查,发现宁蒙灌区排水的pH、TN、TDS和NO3--N分别受不同排水沟渠、排水沟渠级别及二者互作的影响。内蒙古九排干排水的TDS和NO3--N浓度受排水时间影响显著,TN、TP、NH4+-N和COD浓度主要受排水时间、沟道级别及二者互相的影响。宁蒙灌区沟底底泥中的全盐含量明显低于边坡,而TN和TC平均是边坡土壤的1.2倍。内蒙古河套灌区沟底底泥中TN、TP和TC的增加比例是宁夏灌区的1.6、3.8和6.3倍。内蒙古河套灌区农田排水水质明显差于同期(8月)的宁夏灵武灌区,其TDS、TN、TP、NH4+-N和COD浓度是宁夏灵武灌区的3.2、2.5、2.8、10.0和1.5倍。宁蒙引黄灌区农田排水污染以氮含量超标为主,尤其以农沟和干沟为主,而磷浓度较低,基本不造成污染。内蒙古引黄灌区各主要排水时期,以8月农沟排水中氮超标和干沟排水中氮和磷污染程度最高。     

Biological Assessment of Water Pollution Using Periphyton Productivity and Standing Crop in the Linggi River,Malaysia

Many assessments of water pollution in aquatic ecosystem have focused mainly on physical and chemical characteristics. However, until recently, biological aspects have been given little attention. Although physical and chemical methods of assessing water pollution are relatively simple to interpret, biological assessments have many strong merits. Therefore an attempt was made to use periphyton productivity (in terms of biomass ash‐free dry weight, AFDW) and chlorophyll‐a content (measured from periphyton colonized on glass microscope slides) to assess water pollution in the Linggi river. The Linggi River is a tropical lotic system in the country of Malaysia. As a result of increased nutrient enrichment due to sewage and agro‐industrial wastes, analyses of accumulated periphyton on glass slides showed increased biomass AFDW from an unpolluted upstream reach to the highly polluted downstream reach of the river. In contrast to biomass, the chlorophyll‐a content of the accumulated periphyton was not always directly related to the AFDW of the biomass. Though the highly polluted Station 4 showed high biomass AFDW and chlorophyll‐a, due to increased nutrient enrichment. The chlorophyll‐a values at slightly polluted Station 2 were lower than at the unpolluted Station 1. Meanwhile, the mean chlorophyll‐a content observed in Linggi river was relatively high as compared to previous studies carried out in Malaysia. When the Water Quality Index (WQI) was calculated using key chemical parameters linked to organic pollution, there was a significant correlation between chemical parameters, biomass AFDW, and chorophyll‐a. Though the chlorophyll‐a content increased with decreases in the WQI, similar to the biomass AFDW, the chlorophyll‐a values were found to be lower in slightly polluted Station 2 than unpolluted Station 1. Therefore it was not necessary that an increase in the biomass AFDW, due to nutrient enrichment, would always increase the chlorophyll‐a in accumulated periphyton (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of contraceptives on the prevalence of vaginal colonization with Candida species in Edo State, Nigeria

High vaginal swabs (HVS) obtained from 500 volunteers in Edo State, Nigeria which comprised 394 contraceptive users and 106 non-contraceptive users were screened for the prevalence of Candida species using standard procedures. Results revealed the isolation of Candida species in 246 of volunteers. These included Candida albicans 174 (38.4%), Candida pseudotropicalis 20 (4%), Candida stellatoidea 15 (3%), Candida krusei nine (1.8%), Candida guilliermondii 12 (2.4%), Candida tropicalis 11 (2.2%) and Candida glabrata five (1%). Of the 394 contraceptive users, 203 (51.5%) had Candida species isolated from them compared to 43 (40.6%) from 106 non-contraceptive users. There was significant relationship (P<0.001) between the type of contraceptive used and the prevalence of vaginal colonization. Age and marital status of the volunteers sampled had significant relationship (P<0.001) with the prevalence of vaginal colonization. Results have revealed an association between use of contraceptive and the prevalence of vaginal colonization in our environment.     

The decline of a Glossina morsitans submorsitans belt in the Egbe area of the derived savanna zone, Kwara State, Nigeria

In the the early 1970s the Egbe area of Nigeria was known to be one of high trypanosomiasis risk, with four Glossina species G. morsitans submorsitans Newstead, G.longipalpis Wiedemann, G.palpalis palpalis Robineau-Desvoidy and G.tachinoides Westwood present. Grazing by Fulani pastoralists used to be short-term and only in the dry season. In recent years these pastoralists have grazed their cattle in the area throughout the year and this has prompted a reappraisal of the tsetse situation. Tsetse populations were sampled for 3 years using hand-net catches from man or an ox and biconical traps. Resident livestock, slaughter cattle and some of the flies were examined for trypanosome infection. Of the four tsetse species previously reported from the area, only the riverine species, G.p.palpalis and G.tachinoides, were encountered during the investigation. None of the 152 G.p.palpalis and 52 G.tachinoides examined was infected with trypanosomes. No infection was detected in 101 slaughtered cattle, 65 live Muturu, twelve goats and two pigs by wet film examination. However, a 14.3% Trypanosoma vivax infection rate was detected by Haematocrit Centrifugation Technique (HCT) examination in twenty-one slaughtered cattle. Increased human activities over the years had destroyed much of the vegetation and depleted the wild-life population to an extent that resulted in the disappearance of G.m.submorsitans and G.longipalpis, resulting in turn in a greatly reduced trypanosomiasis risk. It is likely that a similar trend is occurring in other areas of the Derived Savanna and Forest zones of West Africa as the human population expands.(ABSTRACT TRUNCATED AT 250 WORDS)     

Concentrations and Distribution of Trace Metals in Water and Streambed Sediments of Orogodo River,Southern Nigeria

The distribution of Cd, Pb, Ni, Cr, Cu, Mn, Fe, and Zn in sediment and surface water, and some physico-chemical characteristics of Orogodo river sediments, were evaluated. The sediment pH ranged from 5.1–7.3; conductivity values ranged from 34.5 to 389.0 μScm^?1. Total nitrogen values ranged from 0.06–0.10%, NH₃-N values ranged from 0.25–0.44 mgkg^?1, percent total organic carbon ranged from 0.21–1.68%, and total phosphorus values ranged from 0.004–0.02% for dry and wet seasons. The sand fraction consists of 87–95%, silt fractions ranged from 0–2%, and clay fraction between 4–13%. The mean concentrations of metals (dry weight basis) in the streambed sediments ranged from 1.92–17.37 mgkg^?1 for Cu, 0.98–4.78 mgkg^?1 for Ni, 0.01–32.98 mgkg^?1 for Mn, 353.22–2045.64 mgkg^?1 for Fe, 69.96–100.16 mgkg^?1 for Zn, 0.21–1.32 mgkg^?1 for Cr, and Cd was less than 0.001 mgkg^?1 for wet and dry seasons. The mean concentrations of metals in the surface water ranged between 0.01–0.05–0.05 mg/L for Cu, nd-0.11 mg/L for Ni, 0.001–0.31 mg/L for Pb, 0.001–1.82 mg/L Mn, 0.01–3.52 mg/L for Fe, 0.16–0.61 mg/L for Zn, nd-0.007 mg/L for Cr, and <0.001 mg/L for Cd. Based on principal component analysis, two main sources of metals in the Orogodo River can be identified: (i) Cr, Cu, Pb, and Fe are mainly derived from industrial sources; (ii) Mn, Zn, and Ni associated with traffic activities. No element examined had a contamination/pollution index value greater than unity (pollution ranges). This implies that the multiple pollution indices obtained from the analysis showed that Orogodo River sediments were not polluted with heavy metals.     

Assessment of Water Pollution using Diatom Community Structure and Species Distribution — A Case Study in a Tropical River Basin

A study on biological assessment of water pollution using diatom community structure and species distribution was carried out in the Linggi River Basin, Malaysia which was polluted by various urban, industrial and agricultural wastes. A total of 86 diatom taxa belonging to 21 genera were recorded from all eight sampling stations located in the basin, of which 70 species were found on artificial substrates; the remaining 16 species were recorded exclusively on natural substrates. The number of diatom species observed between the stations varied from 22-47 species. The dominant diatom species in decreasing order of abundance were Eunotia vanheurckii, Nitzschia palea, Achnanthes saxonica, Gomphonema parvulum and Achnanthes minutissima. The most common clean water species were Achnanthes minutissima, A. linearis and Synedra rumpens. The most tolerant species were Nitzschia palea followed by Gomphonema parvulum and Pinnularia braunii. Eunotia vanheurckii and Navicula cryptocephala occurred in high densities at both unpolluted and polluted stations and can be considered as the common facultative or indifferent species. Although a large number of species were recorded at the unpolluted stations, equivalent number of species were also found at the moderately polluted stations. However, the number of species was reduced at grossly polluted stations. Nevertheless, a marked variation in species association exists between the unpolluted and polluted stations, but not among the polluted stations to distinguish the type and degree of pollution.     

The chemical hydrology of the River Oshun, Western State, Nigeria

The changes in the chemistry of the waters of a small river before and immediately after it has been dammed are reported here. Pre-impoundment investigations reveal the paucity of nutrient salts which became slightly more concentrated in the Ientic environment created after the closure of the dam. Also, the fluctuations in the chemistry of the waters were influenced by a number of physical factors notably water level, current velocity and temperature. Deoxygenation of the usually oxygen-undersaturated river waters was not observed after the closure of the Asejire dam built across the River Oshun.     

Water Quality of Effluent-dominated Ecosystems: Ecotoxicological, Hydrological, and Management Considerations

In arid and semi-arid regions of the southwestern United States and other parts of the world, flows of historically ephemeral streams are now perennially dominated by municipal and/or industrial effluent discharges, particularly in urbanized watersheds. Because effluent-dominated and dependent water bodies have previously received limited scientific study, we reviewed select contemporary topics associated with water quality of ephemeral streams receiving effluent flows. Our findings indicate that these ecosystems present numerous challenges to aquatic scientists and water resources managers, including: 1) appropriate ecosystems or upstream conditions used reference sites in biomonitoring are difficult to locate or do not exist; 2) water quality criteria, particularly for metals, are dramatically influenced by unique site-specific stream and land use conditions; 3) effluent-dominated streams represent worse-case scenarios for evaluating and predicting aquatic responses to emerging contaminants (e.g., pharmaceuticals and personal care products); 4) low-flow and drought conditions often preclude effective biomonitoring and water quality interpretation, or skew ambient assessment results; 5) chemical-physical water quality parameters (e.g., dissolved oxygen, conductivity, temperature) are dramatically altered by effluent and stormwater characteristics; and 6) beneficial reuse of reclaimed effluent waters potentially conflict with sustainability of ecological integrity. Subsequently, we recommend several water quality research priorities for effluentdominated water bodies.     

珠江广州市段PFU原生动物群落特征及其与水质的关系

采用国家标准《水质微型生物群落监测－PFU法》,对珠江广州市段的原生动物群落进行了群落组成和群集过程的研究。共观察到各类原生动物203种。其中植物性鞭毛虫44种;动物性鞭毛虫64种;肉足虫17种和78种纤毛虫。分析了原生动物群落在该河段的组成特点,以及它们与水质变化的关系。结果显示：原生动物群落持征的变化与水质变化相吻合,珠江在流经广州市区后,水质发生了明显地恶化,原生动物群落受到破坏;经过一个较长的流程,水质得到了一定程度的改善,原生动物群落也有所恢复。     

水和氮质量平衡模型预测稻田氮的淋溶损失

水和氮质量平衡模型预测稻田氮的淋溶损失曲向荣（中国科学院沈阳应用生态研究所,沈阳１１００１５）Ｋ．Ｋ．ＴａｎＪｉ（美国加州大学水土气资源系,Ｄａｖｉｓ９５６１６,Ｕ．Ｓ．Ａ．）ＡＷａｔｅｒａｎｄＮｉｔｒｏｇｅｎＭａｓｓＢａｌａｎｃｅＭｏｄｅｌｆｏｒＰ...     

国内外森林与水质研究综述

近几十年来,随着大面积的森林被不合理的采伐利用,使生态环境遭受巨大破坏。同时,近些年来,受全球气候异常的影响,水、旱灾频繁,水土流失严重,且由于环境污染,造成水质不断恶化,水质型缺水日益严重。为保护水资源,森林与水环境,森林与水质已成为近十年来森林水文学研究的重点和热点。国内外的一些专家、学者经过多年来的观测和研究,已取得很多成果。1　关于森林和水质的研究现状大约从本世纪50年代,我国开始关注森林对水质的影响[1]。不过国内绝大多数的研究是着重于森林对河流悬移泥沙含量的影响。直到七十八十年代,我国的一些科研院所,如…     

Hooded Vultures Necrosyrtes monachus nearly extirpated from Edo State,Nigeria: a report on the avian scavenger community

Avian scavengers, by feeding on carrion and other organic matter, provide critical ecosystem services. Vultures, the only obligate avian scavengers, have reportedly experienced massive population declines in Africa yet current knowledge regarding their status in most West African countries is unknown. This study set out to ascertain the status of the avian scavenger community in Edo State, southern Nigeria. We made total counts of all scavenging birds at foraging and roosting sites in 13 urban areas. We recorded three species of avian scavenger which were, in order of decreasing relative abundance, Pied Crow Corvus albus, Yellow-billed Kite Milvus migrans and Hooded Vulture Necrosyrtes monachus. There was a positive correlation between relative abundance of avian scavengers and human population size, such that more populous urban centres had larger populations of scavengers. We counted more scavenging birds at roosting sites than at foraging sites. While the Pied Crow and Yellow-billed Kite appear to be thriving in Edo State, the Hooded Vulture appears to have experienced a massive population decline. Our results suggest that without immediate conservation effort such as protection, education and advocacy, the Hooded Vulture will be extirpated from this region in the near future. We suggest that these conservation efforts be focused on the largest urban areas. Furthermore, we recommend that other states in southern Nigeria be urgently surveyed in order for more general conclusions to be drawn about the fate of avian scavengers in this region.     

基于大型底栖无脊椎动物群落的上海市河道水质生物学评价

2011年夏秋季,在上海市全境83个河道断面开展了大型底栖无脊椎动物采样,共获取底栖动物20个分类单位(种).9个极严重污染断面未采集到活体大型底栖生物,生境基本丧失.其余74个有活体生物断面,采用三种常用生物指数:Shannon-Wiener多样性指数、Hilsenhoff耐污指数、Goodnight修正指数分别进行计算及评价.Shannon-Wiener多样性指数判别为25个严重污染和49个重污染断面;Hilsenhoff耐污指数划分38个重污染、5个中污染和31个轻污染断面;Goodnight修正指数划分33个重污染、2个中污染和39个轻污染断面.与典型河道断面的水质理化指标监测值进行对照,Shannon-Weiner多样性指数对河道水质评价的准确度较低,Hilsenhoff生物指数和Goodnight修正指数的水质评价效率及准确度均较高,断面污染等级与水质理化指标基本对应.     

Immunologic,genetic and social human risk factors associated to histoplasmosis: Studies in the State of Guerrero,Mexico

Immunologic and occupational aspects of the susceptible population exposed to Histoplasma capsulatum, the causative agent of histoplasmosis were analyzed in the Mexican State of Guerrero. Three areas were studied, Juxtlahuaca, Olinala, and Coyuca; in the first two, their populations refer contact with bat guano and/or avian excreta, which contain nutrients for fungal growth, while the Coyuca population referred no contact with the above mentioned excreta. Previous infection with H. capsulatum was determined by histoplasmin-skin test, and the response was higher in men than in women (93.87, 85.71, and 6.6% for men, and 78.94, 66.6, and 0% for women) in Juxtlahuaca, Olinala, and Coyuca, respectively. Labor activities related to a persistent contact with the fungus were considered as an occupational risk factor, histoplasmin-skin test reached 88.57 and 36.36% of positive response in individuals with high and low risk activities. A high percentage of histoplasmin responses was observed in subjects with constant contact with H. capsulatum, such as, cave-tourist guides, peasants, and game-cock handlers, and generally they developed the largest diameter of skin reactions. Genetic risk factor was determined by studying the gene frequency of the Major Histocompatibility Complex antigens in a sample of individuals and their first degree relatives in Juxtlahuaca, Olinala, and Coyuca. Significant differences were found for HLA-B22 and B17 antigens in Juxtlahuaca, and for HLA-B22 in Olinala, in comparison to the usual gene frequency observed in the normal Mexican population. HLA results were important, considering that HLA-B22 was previously found to be possibly related to pulmonary histoplasmosis in Guerrero. This revised version was published online in June 2006 with corrections to the Cover Date.